US Passport Number Regex for PHP

What this pattern does

This page provides a well-structured, multi-part regular expression for matching us passport number, ported and verified for PHP. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. The snippet below is ready to drop into your PHP project — whether you're validating in a Laravel validator, a WordPress plugin, or a standalone PHP script.

Php Implementation

<?php
// US Passport Number
// ReDoS-safe | RegexVault — Identity & PII > Passport Numbers

define('US_PASSPORT_NUMBER_PATTERN', '/^[A-Z][0-9]{8}$|^[A-Z]{2}[0-9]{7}$/');

function validate_us_passport_number(string $input): bool {
    return (bool) preg_match(US_PASSPORT_NUMBER_PATTERN, $input);
}

// Example
var_dump(validate_us_passport_number("A12345678")); // bool(true)

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Passport Numbers category and carries a ReDoS-safe certification. That matters for PHP developers because especially relevant in PHP where PCRE backtracking limits can trigger silent failures on malicious input. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

US passport books use 1 letter + 8 digits. US passport cards also use 9 alphanumeric characters. Older US passports may have different formats. The State Department does not publish the exact checksum algorithm.